fix RowReduce on improperly sized nested lists
handle sympy RuntimeError bug in Limit[]
add previously failing Integrate tests
add TODO to Plot
add TODO to Eigenvectors
add failing test to Integrate
fix bug in Eigenvectors: zero eigenvectors
fix bug in Plot: Invalid AspectRatio should not raise NumberError
Merge pull request #110 from sn6uv/ServerErrors

Server error fixes